1. Field of the Invention
This invention relates to the formation of shelf-stable food products from protein source materials, and more particularly, relates to a process for producing an intermediate moisture food product.
2. Description of the Prior Art
During recent years, extensive research and development efforts have been applied toward the development of meat-like or meat simulating food materials prepared from secondary protein sources, particularly protein-containing vegetable substances. Such materials desirably present the appearance, texture, taste and apparent moist eating quality of meat and meat-type foods.
Among such materials are those known as intermediate moisture food products, that is, those having a moisture content in excess of 10% and substantially below 75%. These materials result from the processing of protein-containing vegetable materials, and they exhibit a resemblance to actual meat in appearance, texture, and chewing and mouth feel characteristics. These materials have been found particularly acceptable for use as an animal food in that they demonstrate a high degree of palatability such that the animal receives them favorably.
A variety of processes for producing such intermediate moisture food products is known to the art. Loepiktie, et al., U.S. Pat. No. 3,759,715, disclose a process comprising the preparation of a dough from secondary protein source materials such as vegetable source materials having at least 30% protein and an aqueous liquid containing various humectants and preservative solvent materials. The dough is thereafter subjected to a mechanical tempering operation, followed by controlled, unidirectional expansion, placing the dough in a tube unconfined at the ends, and subjecting the tube to elevated temperature and pressure to heat-set the protein.
Van Middlesworth, et al., U.S. Pat. No. 3,745,021, discloses an expanded, shelf-stable food product comprising meat, a farinaceous component, water, and water soluble solutes, including sugar. The product is produced by combining the ingredients and heating to cause partial gelatinization. The soluble bacteriostatic components are then added and the resulting mix is then subjected to extrusion at elevated temperature and pressure to form an expanded "rope", which is then cut to form chunks of the product.
Burkwall, Jr., U.S. Pat. No. 3,759,714, discloses a high flavor proteinaceous food product comprising flavoring agent, sugar or equivalents, pregelatinized starch, a high protein binding agent, and sufficient water to give a final moisture content of from 20-40% by weight. The product is produced by mixing all of the above constituents, heating the mixture to a temperature below the boiling point of water and thereafter extruding the heated mixture into small strands.
Yang, et al., U.S. Pat. No. 3,814,823, disclose a process of forming a meat-like, protein-containing product having unidirectional parallel fiber structure produced by stretching.
Hayes, et al., U.S. Pat. No. 3,886,298, disclose the preparation of expanded texturized protein products which have a fibrous aligned meat-like appearance.
Buck, et al., U.S. Pat. No 3,653,908, disclose the preparation of an animal food product containing stabilizing solutes, including sugar, salt and acidulants to provide bacteriostasis which is heated and extruded.
The prior art, then, discloses a number of processes for producing an intermediate moisture food product which, however, require expensive, special operative steps; result in products containing excessive amounts of water; which have inadequate storage stability due to poor bacteriostatic properties; and require the utilization of expensive protein source materials (meat).